The use of a knife jig at the sharpening of a knife in a grinding machine with a rotating grindstone is conventional. The jig has a clamp for holding the knife, and the jig may be manually operated during the sharpening process, preferably supported by a rod-shaped universal support of the grinding machine.
A problem with such a knife jig relates to the dimensions of the knife blade to be held by the clamp. The blade must normally have a length of some 60 mm and width of some 14 mm to be properly held by the clamp and satisfactorily sharpened by the grinding machine.
Small woodcarving knifes are normally very difficult to mount parallelly, so that an equally large grind bevel is obtained at both sides. The reason is that the blade is only parallel over a very small area close to the handle.
The main object of the invention is to increase the versatility of the knife jig, so that it can be used for a broader range of dimensions and shapes of the knives to be sharpened.
The Invention
This object is according to the invention attained by the addition to the knife jig of a knife holder with means for holding the knife and with a flat rod to be clamped by the clamp of the knife jig. The result is a knife jig assembly comprising the conventional knife jig and the inventive knife holder having a flat rod, which can be simply and securely held by the knife jig clamp. The operation of the knife jig assembly at sharpening is very similar to the operation of the knife jig alone.
The means for holding the knife may preferably be two pairs of open jaws attached to the flat rod and a closed-loop yoke between the jaws, the yoke being movable for engaging the knife.
Surfaces of the jaws intended for cooperation with the handle of the knife may preferably be concave in all directions, which means that the knife handle bears against four points of the jaws.
In a threaded hole the yoke may be provided with a screw for engagement with the flat rod.